1. Technical Field
The present invention relates to a method for supplying cooling medium to a grinding cup for grinding buttons of a rock drilling bit. The grinding cup includes a shank that is rotatably mounted in a grinding machine and a wear part having a recess. The recess carries out the grinding of the buttons. The invention also relates to a grinding cup that is intended to be rotatably mounted in a grinding machine. The grinding cup carries out grinding of buttons of a rock drilling bit. The grinding cup includes a shank and a wear part, with the wear part having a recess. The grinding cap is supplied with a cooling medium.
2. Prior Art Background
When grinding cemented carbide buttons of a drill bit, a grinding cup of the type described above is normally used. The wear part of such a grinding cup usually has an abrasive grinding surface that often includes granular diamond. However, the grinding of cemented carbide buttons generates both heat and abrasive cuttings to such an extent that it is necessary to cool the grinding cup and the button bit as well as flushing away the cuttings. The known prior art technique for such cooling is to supply cooling medium, normally water, through the grinding machine and axially through the grinding cup to provide the cooling medium to be discharged in the region where the wear part of the grinding cup engages the free end of the button. This arrangement requires that the cooling medium must be guided through the grinding machine to the rear end of a shank of the grinding cup and then axially through the shank of the grinding cup to the free end of the wear part. It is recognized that the provision of means for achieving such a cooling medium supply is a restriction from a designing point of view, i.e., when designing the grinding machine a lot of attention must be paid to the guiding of cooling medium through the grinding machine and consequently the machine may become relatively complicated.